


Tied Up With A Bow (Seteth’s Birthday)

by fyrefalcon



Series: fyrefalcon's 2019 setleth week [4]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Birthday Sex, Cunnilingus, Explicit Sexual Content, F/M, Light BDSM, Light Bondage, Light Dom/sub, Porn with Feelings
Language: English
Status: Completed
Published: 2019-12-27
Updated: 2019-12-27
Packaged: 2021-02-26 06:54:06
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,719
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21989137
Author URL: https://archiveofourown.org/users/fyrefalcon/pseuds/fyrefalcon
Summary: seteth's birthday present is a present for us all.
Relationships: My Unit | Byleth & Seteth, My Unit | Byleth/Seteth
Series: fyrefalcon's 2019 setleth week [4]
Series URL: https://archiveofourown.org/series/1577812
Comments: 3
Kudos: 127





	Tied Up With A Bow (Seteth’s Birthday)

**Author's Note:**

> i know it's not cool to rate your own smut but: a+, would bang again.

Just after the midday bells, Seteth heard Byleth’s familiar knock on his office door. 

He suspected he wasn’t getting anything else done for the day. 

If he was honest with himself, he was surprised he’d been left alone to accomplish as much as he had, between Flayn’s protesting any work on St. Cichol’s Day whatsoever and Byleth’s tendency to distract him in the most pleasurable ways he could imagine. 

Part of him still couldn’t believe this was his life. Another part, a small part that was getting smaller, shook its head at his lack of self-control. 

Ah well. Goddess forgive him for indulging, as Leonie often said.

“Come in, Professor.” 

The door swung open, revealing Byleth’s customary inscrutable expression. He considered that perhaps she was just here on business after all, but then he noticed the gift in her right hand. 

The small box was perfectly wrapped, with delicate white paper and a red bow. 

She smiled and said, “I have a number of errands to attend to yet today. But I had a moment of freedom, and I didn’t want you to think I’d forgotten your birthday.”

She crossed the room and placed the gift on his desk before squeezing his shoulder, and something within him relaxed with even that small contact. He didn’t know how he’d survived nearly a millenium alone, now that he had this woman by his side. 

If only things were different, and they could conduct their relationship out in the open. 

_Some day,_ he promised himself. _When this war is over._

But for now he’d have to content himself with these stolen moments between their many responsibilities, and keep her content with the same.

As if sensing his thoughts, Byleth squeezed his shoulder again. She kissed his temple at his hairline, and said, “Open it while you’re alone.” 

Something in her tone ignited a flash of heat within him. He met her eyes, but they disclosed nothing. 

She smiled and patted his shoulder with a cheeky familiarity that would have been hard to imagine from her five years ago. Her eyebrows raised just a touch, and she said, “I’ll see you in a few hours.” 

A moment later, she was gone, closing the door behind her. 

Seteth looked at the gift she’d left behind. _There is no time like the present,_ he thought, dryly amused with his own wordplay, and he untied the red ribbon, unwrapping the white paper carefully. The box underneath the wrapping was also white, and he lifted off the top of the box to reveal the contents within. 

Byleth had tucked a silky red cloth inside, which enclosed and obscured the object within, and a slip of paper rested on top of it. He unfolded the note, revealing her strange penmanship: 

_Dear Seteth,_

_I’m sending Flayn on an errand with Lindhardt and Caspar, with instructions to purchase something special for your evening meal. Both have promised to protect her._

_This gift should help distract you until she returns._

_I’ll see you in your chambers after the afternoon bells. Happy birthday, my love._

_Byleth_

Seteth felt his anxiety spike, and he breathed through it, trying to calm himself down. He knew Byleth wouldn’t willingly put Flayn in danger, and she had made the trip to town herself, before. 

He hoped they would at least take Flayn’s battalion along, and he wondered if he should contact them to ask. And then he remembered the rest of the gift in his hand. 

He set Byleth’s note on the surface of his desk and unfolded the fabric in the box to reveal its contents.

Underneath the silky cloth was a single coil of the softest rope Seteth had ever felt. He was puzzled for a moment until he tipped the entire package out into his other hand. 

The cloth was larger than a handkerchief, large enough to be--

A blindfold. And...a rope. 

_To restrain her,_ his mind offered, and he immediately imagined her bound and naked, tied to the headboard of his bed, writhing deliciously...

Byleth was right. This would be _quite_ distracting.

*

Three agonizing hours later, Seteth closed his office door behind him, clutching the rope and blindfold in a small bundle against the small of his back, hoping they would stay concealed under his cloak. 

As he turned around, a familiar brogue rang out down the hallway. “Why, Seteth. Could it be that you’re actually leaving your desk early for once?” 

_Manuela._ He closed his eyes and exhaled. _Of course._

“Yes, Manuela.” He bowed shortly, keeping his hand with Byleth’s gift concealed. “I am.” 

“Are you ill? I’d be happy to take a look at you...in the infirmary.” She winked. “Or otherwise.” 

“I’m quite well, thank you. That won’t be necessary.” 

Manuela looked him over, eyes narrowing. “So what brings you out of your cave, then, Seteth?”

He smiled tightly, wishing for this encounter to be over already. “It is my birthday.” 

Her eyes widened. “Oh! You don’t say! Well, in that case, I won’t keep you. I’m sure you have something lovely planned with Flayn.” 

Certainly it wouldn’t hurt to lie, in this case. “I do, indeed.” 

Manuela smiled. “How nice. Well, Seteth, if you find yourself lonely...for some _adult_ companionship later, you know where to find me.” 

If she only knew the truth of where he was headed...as soon as he could extricate himself from this conversation. He supposed Manuela might actually faint from the shock of it. 

Seteth bowed again. “Thank you for the offer, Manuela, although it’s hardly necessary--” 

“Oh, I know it’s not _necessary_ . I just can’t bear the thought of you being _alone_ on your _birthday,_ after all…” She fixed him with her doe-eyed look and it took every fiber of patience remaining in his body not to sigh or simply walk away. 

“I do appreciate your concern. Good day, Manuela.” 

She chuckled breathily, waving goodbye, wiggling each of her fingers in turn. “Good day, Seteth,” she parroted him, adopting his formal clip in a way that danced over Seteth’s last nerve. “Do have yourself a happy birthday.” 

Nodding to her once again, he turned towards the audience chamber and was safely in the dark of the stairwell to the third floor before she could draw breath to speak again. 

He supposed that it was gift enough for Manuela to confirm that she still believed that he was available. His relationship with Byleth hadn’t even made it into the rumor mill.

He remembered she was waiting for him, and he felt his erection press against the seam of his pants. He took the stairs two at a time, allowing himself to feel his own urgency in the privacy of the stairwell. 

Seteth opened the door to his chambers and stepped inside, closing the door hastily behind him, exhaling with the click of the latch. He turned.

Byleth had already let herself into his quarters, and she was stark naked, sitting in his chair, sipping a glass of wine, her legs crossed delicately at her ankles. 

Her face was blank, besides the suggestion of a smile. “Hello, Seteth. Happy birthday.”

He tried to respond, and the sound came out somewhere between a cough and a whine. He locked the door behind him. 

He wondered headily whether he was going to survive this affair with this woman or if her penchant for driving him insane with lust would be the death of him. 

He found his voice, lifting up the bundle. “Thank you for the gift.” 

She stood, crossing the room to stand before him. “My pleasure.” Her voice was straight, with no hint of a joke, and Seteth realized that he had nothing on emotional control compared to her. “I’m ready when you are.” 

Seteth could feel his pulse echoed in his cock, and he felt almost dizzy with arousal. “I am ready.”

She headed towards his chambers, grabbing the bottle of wine and the two glasses from the table in the common room on the way. From halfway across the room, he watched the sway of her hips, the curve of her waist as it blossomed into her full ass. 

He remembered watching her depart from behind, so many times, imagining just this under that strange getup she always wore. 

She glanced behind her when she didn’t hear him follow. “Are you coming?” 

He chuckled. “Yes. I’m coming.” 

He followed her into his own room, and she placed the wine glasses on the table next to his chair, in a strange echo of another day where Seteth had been driven to distraction imagining a liaison with her hours before it had materialized. 

There had been more such days than he could have ever expected. He supposed he shouldn't be surprised, but Byleth was a phenomenal, confident lover, and he didn't take a second of her attention on him for granted.

She turned to face him once they were both in his room with the door locked behind them. “Flayn will not be back before the evening meal. I promised Lindhardt uninterrupted access to the Holy Mausoleum for his cooperation--and for no questions.” 

Seteth nodded, swallowing. He tried to watch her face and yet couldn’t tear his eyes from her full breasts and the swell of her stomach, soft over the muscles he knew were underneath.

“It was actually his idea to bring Caspar,” she said lightly, and Seteth was reminded of her manner in faculty meetings, except now she was naked, and now she was sitting on the edge of his bed, her legs open just enough to be suggestive. “He thought it would make you worry less.” 

“Kind of him,” Seteth murmured, not wanting to think of anything at all, besides this woman in front of him. He supposed it did ease his fear over Flayn, which even now battled for domination against the feelings of arousal, heavy and urgent in his chest. 

His need for her made his throat tight.

She smiled and offered him her wrists. “Shall we get started then?” 

He crossed the room, pressing his lips to the soft skin on her upturned wrists, the translucent skin where her pulse should be. They were still warm, though, and faintly scented with the fragrance she had chosen for this occasion, something musky and decadent that sidestepped his thinking mind and rewired him into even deeper arousal.

He was eager to dive in, but first, he walked himself back from the edge to make his intentions clear to her. “I have something to ask of you, before we begin.” 

Byleth watched him, expectant. “Of course.”

“Will you stop me, if you feel uncomfortable?” He met her eyes. “I very much want this, but need to know I can trust you to tell me to stop, if you need to.” 

“You have my word, Seteth.” 

He nodded, his voice absent. 

He unfolded the bundle he was still clutching, and dropped the red blindfold onto the bed while he bound Byleth’s offered wrists. He’d done this to dispatched enemy combatants enough times to know how to securely restrain her, although he was careful to make the bindings loose enough so that she wouldn’t be in pain. 

As he finished the binding on her second wrist, he felt a spike of arousal at the sight of the red rope contrasting against her milky skin, and he stilled for a moment, weathering the wave of the sensation. 

He was almost faint, he was so turned on by this. Perhaps Manuela wouldn't be the one to collapse after all. 

He urged himself to move, using his hands to guide her body back on his bed, arranging the sheets and pillows around and behind her, fastening the ends of the ropes to his headboard to keep her exactly where he wanted her. 

“Are you comfortable?” he asked, pressing kisses into her neck. 

He felt his cock twitch as his hands moved along against her uncovered skin, palming her breasts, laying his hand on the soft rise between her legs. 

She nodded. 

He stepped back, reaching to his neck to unbutton his high collar before continuing down the front of his robes. She murmured with appreciation, and he was so deeply satisfied that she found him as attractive as he had always found her.

He shrugged off his robes, laying them gently over the foot of the bed, before unfastening his boots and then his pants, and then the underclothes beneath, taking his time, allowing her to watch him, until he was as naked as she was. 

She regarded him and his erection with half-lidded eyes, and the high flush on her cheeks told him that this gift was as much for her as it was for him.

Something about _that_ was delectable, and he promised himself he would unpack his thoughts about that later. 

“I’m going to blindfold you now,” he said, and she nodded again.

He retrieved the silky blindfold from the coverlet on the side of the bed and folded it over upon itself until it was a long, narrow strip. He climbed on top of her, straddling her around her waist, feeling delightfully apprehensive and incredibly aroused. 

He brushed her bangs out of her eyes with one hand, kissing her almost chastely. “This is already the best gift I have ever received in my life, Byleth.” 

He met her gaze so she could see the truth of it, and then settled the fabric over her eyes. She lifted her head so he could tie the cloth behind her. He knotted it securely, so she wouldn’t dislodge it by moving around. 

He wanted to make her squirm without the blindfold coming undone.

“Are you still okay?” he asked. 

“I am.” 

“Exemplary.”

He sat back on his haunches, already excited by the fact that she couldn’t see him, that she was his to stroke and pleasure as he pleased. He shifted back, moving next to her, and gently pushed her legs apart for better access to the core of her. 

He brushed his fingertips along the inside of her thighs, touching her along the low line of her belly, watching her breath hitch in her chest. He ran his hand over the soft mound between her legs again, with some pressure this time, and her hips pushed up to meet his hand. 

He slid his fingers down between her legs and she was already very, very wet, and he couldn’t help the low murmur of appreciation in the back of his throat. 

If he was honest, the fact that he didn’t have to be silent with her in fear of his daughter overhearing was present enough. 

Byleth knew it too, and the sounds she was making as he used one hand to spread her open and the other to trace the soft curve of her clit were making him near feral. 

He took a deep breath, settling himself, urging himself back to patience. This was his gift, and he was going to savor every second of it. 

He slipped off the side of the bed, leaving her tied there, watching her squirm. “Seteth?”

“I’m here.” 

He walked around the bed and approached from the other side, touching her randomly--his fingers skimming her left breast, lingering on her nipple. His nails on her arm and down the side of her torso, firm enough not to tickle, but not hard enough to leave lines on her soft skin. 

His mouth on her mouth. Her chin raised, and she kissed him deeply, hot, hot with need. Seteth pushed his tongue into her mouth, feeling her hips push up against nothing, and then running his hand between her legs once again, feeling her moan deep in the back of his own throat. 

He broke off the kiss, working his way down her torso, planting a kiss on the curve of her breast, on the old scar on her side, on the soft skin just underneath her belly. He kissed the peaks of her hip bones, breaking away once again to sink his teeth into the curve of her hip.

She writhed underneath him, and it was exactly as tantalizing as he had imagined. 

She didn’t beg for him, but he was familiar enough with her pacing that he knew she would be absolutely aching with need, and so he made his way to her middle once again, leaving marks with his mouth across the expanse of her thigh. 

A memory of him, for later. He hoped.

He pushed her thighs open, and rubbed his thumb up the core of her, pressing on her clit. She shivered, and he captured her bud with his mouth, eliciting a strangled moan from the woman who was tied to his bed. 

“Oh, Seteth, yes. Please, please--right there, just like that…”

He half-expected to feel her hand in his hair, guiding him, before he remembered he’d tied it to his bed. Instead, she ground against him, moving enough to make his job difficult. 

He remembered he was in charge here.

“Byleth, be still.” 

She sighed with a mix of arousal and exasperation but complied, and he took advantage of the ease of access, wielding his tongue against her clit, tasting her, feeling her stiff beneath him from the effort of holding herself still, slipping first one, then two fingers inside of her. 

She was making breathy little pants, trying to comply with his directive, and it made him so fucking hot for her he thought he might come into the sheets from just the sound of it. 

He could feel her tighten around his hand as he penetrated her with his fingers, and he knew she was close. He nuzzled his face into her, sucking her clit into his mouth, pressing up with his hand into her slick arousal. 

She moaned, low and long, and the air of his bedroom was punctuated with nothing besides her delicious voice and the slick sounds of his hand inside of her. 

He pulled away for just a moment, and spoke into the room, drawing some of his authority into his voice. “Come for me, Byleth. At once. Come for me…”

He returned his mouth to her clit, flattening his tongue against it once again, and she spasmed around his hand, blossoming heat.

“Oh, Seteth, I’m coming, I’m--” The rest of her statement dissolved on a keening moan.

He hadn't considered that she could be loud enough to be heard _outside_ his chambers, and his pulse quickened with the thought of being overheard.

Pumping through her orgasm with his hand, he longed to feel her contractions on his dick, remembering the delicious, delirious pleasure of feeling her orgasm from the inside on his own arousal.

He pulled away, taking advantage of her condition to survey her, seeing the flush of heat in her neck and the sharp peaks of her nipples, erect with her arousal. 

She was so beautiful. 

She writhed, waiting for him to return to her, and he said, “I thought I told you to hold still.” 

She made a breathy sound of assent, and he could see the color deepen on her chest. He bent forward, catching her nipple between her teeth, and he could feel her tense, holding herself still, expressing her desire for him in an almost-anguished sound of need while struggling against her own desire to move against him. 

He sat back and looked at her once again, her mint hair wet with her own sweat and stuck to her face, her arms above her, pulling lightly at her binding, her chest rising and falling with her shallow, aroused breaths. 

She was exquisite. 

“Holy _fuck_ , Byleth, I am so turned on by you right now.” 

Her lips curved under the blindfold, no doubt a response to his vulgar tongue. 

He leaned toward her, nudging his throbbing erection inside of her, savoring the feeling as he pushed forward, slowly hilting himself and allowing every sensation to ripple into the rest of his body before igniting into an all-consuming heat. 

“I’m going to fuck you now,” he said, leaning close to her ear. 

“Please, please, oh--” She let out a strangled moan. “Yessss.” 

He pumped into her, feeling the heat in his body contract until it was a fire in his balls, fought to keep his eyes open, watching her squirm around him, feeling her clench again, almost at the edge already, so soon. 

“Oh, Byleth, I’m close, I’m--” 

She broke first, crying “Seteth,” and the spectacle and the sound of his name from her lips pushed him over the edge. He followed her, bellowing his release into his room between clenched teeth. 

His orgasm broke over him in waves, each one more intense than the last. Every thought was wrung from his mind like a rag, save one: Byleth. He melted into his own pleasure and his love for her.

Spent, he felt the stress of the earlier hours of anticipation leach out from his muscles, and it was an effort to hold himself above her, protecting her from his weight.

He drew back, cupping his hand beneath their joining to keep from soiling his sheets. Once he was clean enough, he returned to her, pressing kisses into her softness as he reached up to loosen the rope from the headboard. 

He untied her wrists and her arms wrapped around him immediately. He removed her blindfold, and she rested her head, heavy, against his torso.

“Happy birthday, Seteth.” He could feel the curve of her smile against his bare chest. “Did you enjoy yourself?”

He felt almost silly responding. There was no way she could have misinterpreted his enjoyment. Still, he explicitly answered her question. “I absolutely did.” 

She looked up at him, and he could see an echo of amusement in her eyes. “Well, these gifts are yours to keep. You’re welcome to use them whenever the mood strikes.”

The implications of her response stirred heat in his belly once again, and he was impressed with himself. 

Perhaps the fire hadn’t left his blood after all these long years after all.

For the first time in a long time, Seteth felt hopeful about the year opening up before him: the first full year of his long, long life with this enigma of a woman at his side.

***

**Author's Note:**

> official setleth week is almost over, but every week is setleth week around here. i'm bad at twitter, but i promise to share all of my setleth smut and otherwise: @fyre_falcon
> 
> (also, I've not written anything for free day tomorrow, so if there's something you are dying to see, tell me!!!)


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